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From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
	dietmar.eggemann@arm.com, Morten.Rasmussen@arm.com,
	yuyang.du@intel.com, pjt@google.com, bsegall@google.com
Subject: Re: [PATCH v2] sched/fair: update scale invariance of PELT
Date: Sat, 29 Apr 2017 00:09:24 +0200	[thread overview]
Message-ID: <20170428220924.mxzs43zyvfqww2ze@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1491815909-13345-1-git-send-email-vincent.guittot@linaro.org>

On Mon, Apr 10, 2017 at 11:18:29AM +0200, Vincent Guittot wrote:
> +++ b/include/linux/sched.h
> @@ -313,6 +313,7 @@ struct load_weight {
>   */
>  struct sched_avg {
>  	u64				last_update_time;
> +	u64				stolen_idle_time;
>  	u64				load_sum;
>  	u32				util_sum;
>  	u32				period_contrib;

> +		if (sa->util_sum < (LOAD_AVG_MAX * 1000)) {
> +			/*
> +			 * Add the idle time stolen by running at lower compute
> +			 * capacity
> +			 */
> +			delta += sa->stolen_idle_time;
> +		}
> +		sa->stolen_idle_time = 0;


So I was wondering if stolen_idle_time really needs to be a u64. Afaict
we'll be at LOAD_AVG_MAX after LOAD_AVG_MAX_N periods, or LOAD_AVG_MAX_N
* LOAD_AVG_PERIOD time, which ends up being 11040.

After that you'll truncate it anyway.. so there shouldn't be a need to
be much larger than that, no?

  parent reply	other threads:[~2017-04-28 22:10 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-10  9:18 [PATCH v2] sched/fair: update scale invariance of PELT Vincent Guittot
2017-04-10 17:38 ` Peter Zijlstra
2017-04-11  7:52   ` Vincent Guittot
2017-04-11  8:53     ` Peter Zijlstra
2017-04-11  9:40       ` Vincent Guittot
2017-04-11 10:41         ` Peter Zijlstra
2017-04-11 10:49           ` Peter Zijlstra
2017-04-11 13:09             ` Vincent Guittot
2017-04-12 11:28               ` Peter Zijlstra
2017-04-12 14:50                 ` Vincent Guittot
2017-04-12 15:44                   ` Peter Zijlstra
2017-04-13  9:42                     ` Vincent Guittot
2017-04-13 13:32                 ` Peter Zijlstra
2017-04-13 14:59                   ` Vincent Guittot
2017-04-13 18:06                     ` Peter Zijlstra
2017-04-14  8:47                       ` Vincent Guittot
2017-04-11 12:08           ` Vincent Guittot
2017-04-11  9:12     ` Peter Zijlstra
2017-04-11  9:46       ` Vincent Guittot
2017-04-13 13:39     ` Peter Zijlstra
2017-04-13 15:16       ` Vincent Guittot
2017-04-13 16:13         ` Peter Zijlstra
2017-04-14  8:49           ` Vincent Guittot
2017-04-19 16:31             ` Vincent Guittot
2017-04-28 15:52 ` Morten Rasmussen
2017-04-28 17:08   ` Dietmar Eggemann
2017-05-03 17:11   ` Vincent Guittot
2017-04-28 22:09 ` Peter Zijlstra [this message]
2017-05-01  9:00   ` Peter Zijlstra
2017-05-02 13:38     ` Vincent Guittot

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